Memory devices are typically provided as internal, semiconductor, integrated circuits in computers or other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and non-volatile (e.g., flash) memory.
Flash memory devices have developed into a popular source of non-volatile memory for a wide range of electronic applications. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Changes in threshold voltage of the cells, through programming of a charge storage structure, such as floating gates, trapping layers or other physical phenomena, determine the data state of each cell. Common uses for flash memory include personal computers, personal digital assistants (PDAs), digital cameras, digital media players, digital recorders, games, appliances, vehicles, wireless devices, cellular telephones, and removable memory modules.
In addition to performing access operations such as read and write, a non-volatile memory device also performs background operations. For example, the memory device might perform a wear leveling operation by moving data around within the memory array of the memory device. Another background operation might be a housekeeping operation that removes obsolete data in order to free up memory blocks to be erased and reused. These operations are performed in the background typically without the knowledge of the host and, in some embodiments, are performed automatically by the memory device (e.g., are initiated without being commanded by the host).
A problem can occur when these background operations are being performed by the memory device without the knowledge of the host. The host can interrupt the background operation by sending an access command or turning off the power to the memory device. This can result in lost or corrupted data and might require the memory device to start the background operation over, thus resulting in a loss of performance.